In order to treat an aneurysm generated in a blood vessel or the like, a method by which to embed a metallic coil in the aneurysm to embolize the aneurysm and prevent it from being ruptured is employed. Such a metallic coil used as an in vivo indwelling member is a secondary coil formed such that a wire of platinum or the like is shaped in a coiled form and extended in a linear manner to form a primary coil, and then the primary coil is further shaped in a coiled form and extended in a linear manner. The metallic coil in the state of the primary coil extended in a linear manner is inserted into the lumen of a delivery catheter and delivered to a desired site. When removed from the catheter, the metallic coil is restored to the state of the secondary coil.
To embolize the aneurysm, it is considered as advantageous in treatment to spread the metallic coil in various directions without confining at one site in the inside of the aneurysm. Accordingly, a secondary shape given to the metallic coil (the shape of the secondary coil) is desirably a three-dimensional shape likely to intricately spread, not a two-dimensional coiled shape extending linearly as described above. Therefore, there have been proposed secondary coils having such a three-dimensional shape.
For example, Patent Document 1 discloses a substantially spherical or elliptic spherical secondary coil and a method for producing the same. The secondary coil is formed by winding a primary coil around a substantially spherical or elliptic spherical core and thermally shaping the coil.
In addition, Patent Document 2 discloses a method for producing a spherical secondary coil. The secondary coil is formed by winding and shaping a coil around mandrel in which one or more metallic rods are radially erected on the surface of a spherical core. Patent Document 2 also discloses a method for providing a secondary shape by the use of a “candy mold”-type tool. According to this method, a spherical secondary coil is obtained by shaping a coil in a spherical lumen.
Further, Patent Document 3 discloses a method for producing a spherical secondary coil. The secondary coil is formed by fitting a primary coil into a groove in a spherical shaft that has in the surface the groove into which the primary coil is to be fit.
Moreover, Patent Document 4 discloses a secondary coil having a three-dimensional orthogonal shape and a method for producing the same. The secondary coil is formed by winding a coil around a mandrel with a three-dimensional orthogonal shape and thermally shaping the coil.